We must cool the Arctic before it's too late

The decline of Arctic sea ice demands a response, writes Matthew Worsdale. As Arctic temperatures rise, so does the danger of huge eruptions of methane - a powerful greenhouse gas - that will tip the climate into 'hot'. The only solution is geo-engineering.

By any economic argument, it is so much cheaper to cool the Arctic than to deal with the devastating consequences. An abrupt discharge of a large quantity of methane would cause catastrophic climate change coming with a $50-100 trillion price tag.

Imagine if every person on the planet had the knowledge that there was an imminent crisis and an action they could take to make a solution more possible.

The crisis I outline here is the rapid melting of the Arctic, a situation of a gravity that is not appreciated by society.

In simple terms, the Arctic sea ice is a feature of our planet that has existed continuously for the entire duration of human history, and longer - around 2-3 million years.

Yet it stands to disappear at the end of summer within a few years. We could have 6 months free of ice within a decade.

It's already happening - and much faster than predicted

Over just a few decades, the area of the ice sheet and it's thickness have declined rapidly, with an exponential trend.

The dramatic shrinkage of the ice in the summer of 2012 saw the minimum total volume of ice down by 75% compared to the corresponding value when satellite observations first started, in 1979.

The rate of loss is much quicker than predicted by the IPCC, who projected in 2007 that two thirds of the 1979 amount would be present in the summer in 2100. This is a reflection of the fact that the Arctic is warming very much faster than anyone predicted, with huge implications for global warming.

The most visible consequence of Arctic warming is an escalation of extreme weather in the Northern Hemisphere - as the Jet Stream, which is driven by the difference in temperature between the pole and the equator, travels more slowly with increased waviness.

This brings long periods of fixed weather in a given place, such as a searing drought or never-ending rainfall, with little relief - a catastrophe for farming, wherever you live.

An exponential trend to no sea ice

The decline of the ice is represented by both its thinning and the reduction in the area of the Ocean it covers, which in 2012 was about 1/3 of the 1979 value.

The area of the ice is the important property in terms of climate change, corresponding to the total reflectivity of incoming sunlight, or 'albedo'.

The fact that volume is falling faster than the area means that when the ice finally disappears for the first time in summer, there will be a sudden crash in the area and hence, of the albedo.

It is now acknowledged though less often related by scientists whose work involves the sea ice that it is on a downwards exponential trend to zero in the summer months, passing this point within years, not decades.

A claimed 'recovery' of the ice in summer 2013 is put in doubt by the latest data, which suggests that unusually high Arctic temperatures in the first part of 2014 have set the ice back towards values at the start of the melt season in previous years leading up to the 2012 minimum. A likely El-Nino event later this year could contribute further to another record melt.

What is greatly unappreciated by the public is the danger of methane releases. An estimated 1,400 Gt of frozen methane 'clathrate' deposits lie on the seafloor of the Arctic Ocean.

The release of less than 1% of this amount would double the methane in the atmosphere, currently at around 5 Gt - and trigger huge changes in climate of a kind not seen for many millions of years.

The Greenland ice sheet

Loss of the sea ice will make the collapse of the Greenland Ice Sheet all but inevitable, with a sea level rise of up to 7 meters this century.

Methane discharged from the thawing Arctic, due to both land permafrost and precarious frozen hydrates on the seafloor, already appears to be growing exponentially.

The potency of methane as a greenhouse gas - 84 times as powerful as CO2 over a 20 year horizon - ensures that this source of global warming alone could seal the fate of most life on the planet.

The above points illustrate a climate crisis spiraling out of control. Greenhouse gas emissions triggered this process but stopping their emissions, however rapidly, cannot halt the decline of sea ice, as claimed by Greenpeace in their Save the Arctic campaign and many others.

The culprit is albedo feedback - as ice area is reduced, the Arctic absorbs more heat, leading to more ice retreat. We now have a few years at best to put the brakes on the process, to reduce the heat flow into the Arctic dramatically, by preserving the sea ice and doing as much as possible to mimic its reflectiveness.

We must re-engineer the planet

While talk of it remains controversial, the only option is intervention in the climate system - geoengineering - to increase the proportion of the sun's heat that is reflected away into space. We can do this by raising the reflectivity or albedo of the atmosphere, or of clouds or land surfaces.

The fastest and simplest way to do this is to mimic a natural phenomenon we know cools the climate on a global scale. A volcanic eruption emits vast quantities of sulphur dioxide, SO2, into the atmosphere and in the case of the eruption of Pinatubo in 1991, was sufficient to cool the climate by 0.5C for two years.

The strategy in the Arctic would be to add small quantities of SO2 to the upper atmosphere in the summer months. This would be a low cost option for a few years to buy time to switch to a more sustainable longer term option.

Another technique is Marine Cloud Brightening (MCB) - you can create a whitening of existing cloud formations, by spraying up fine seawater droplets to increase the droplet density, thereby making clouds more reflective.

This would compensate for the effect of lost albedo from the sea ice in the Arctic. Research by UK based engineers is already at an advanced stage and only a modest investment would likely be required for deployment of the technology to produce the spray, by craft or land towers and other essential computer modeling to predict the effects.

The 'black hole' between knowledge and action

Many can see that the Arctic is headed for meltdown without intervention. Yet there is a black hole between science and action. Admitting that we need geoengineering seems to make people question whether we are not in fact already screwed.

But see it as part of a comprehensive action plan, and it makes a lot more sense. The tipping points in the climate system risk taking climate change beyond human control. So the situation demands that we respond to this danger first, with geoengineering coming sooner rather than later.

However, the only long term way to avoid climate catastrophe is to remove the cause of the greenhouse effect. Crucially that means bringing down the concentration of CO2, methane and other important gases in the atmosphere, not just stabilizing atmospheric levels, as there is compelling evidence that climate sensitivity is higher than previously assumed.

Fortunately, there exist feasible methods to do this on a timescale of decades - in particular by accelerating the weathering of the abundant mineral olivine, a natural process which absorbs CO2 from the environment and converts it into innocuous bicarbonate.

We cannot allow 'runaway methane'

A growing number of climate scientists and commentators have recognized the need for geoengineering in the Arctic, such as renowned Australian activist and author of 'Climate Code Red', David Spratt.

In a communication shortly after the record melt in 2012 Spratt, evaluating the likely long term temperature increases from CO2 and the repercussions of Arctic melting, asked of geoengineering detractors, "what's the choice?"

The flagship 350 movement is already supplemented by a less publicised '1250' movement for methane - 1250 parts per billion is estimated by James Hansen to be the safe upper concentration of CH4.

So, geoengineering should be seen as part of the action required to maintain the stable climate that is so fundamental to modern civilization, not because humanity should aim to 'control the climate', but because runaway Arctic warming is something we cannot let happen.

Governments - more interested in oil than planetary survival?

Both the US and UK governments have already been briefed by scientists on what is so obviously a 'national security' threat to all nations.

Yet so far there has been no resolution by the key nations to collaborate in the mutual interest of themselves (and all persons on Earth), presumably because of the possibilities of oil extraction in an ice free Arctic Ocean.

By any economic argument, it is so much cheaper to cool the Arctic than to deal with the devastating consequences. An abrupt discharge of a large quantity of methane would cause catastrophic climate change coming with a $50-100 trillion price tag.